Connecting an MCU to your car's onboard diagnostic systems

Onboard diagnostic systems (OBDs) are found in almost every car these days, providing a very rich set of information about parameters like coolant temperature, RPM, and the like.

The information about all these parameters lets us define the state of the vehicle by diagnosing each and every aspect. Here's a guide to getting started with OBD development using your chosen MCU.

First, a quick overview. OBD-II is the protocol that works in most of our cars that date back from a decade ago until now. It's particularly widespread in cars made in Asia, where almost all makers support the protocol, but it is a global protocol and used in cars worldwide. You can find more on OBD here.